Method for printing security documents using sheets with identifiers

ABSTRACT

For manufacturing security documents, a plurality of security documents are printed on a sheet The sheets are being processed in batches ( 15   a,    15   b ). Each sheet carries a unique, machine readable identifier. During manufacturing, the batches are processed by several printing stations ( 10 ). At each printing station, the identifiers are read by a local computer ( 13 ) attributed to the printing station. The results are transferred upon request in data packets to a central data base ( 16 ). Each data packet contains the information for several sheets, which obviates the need to transfer the corresponding data in real time over the network. To increase security and decrease network dependence, each local computer is equipped with the means to check the processing status of a batch autonomously.

TECHNICAL FIELD

[0001] The present invention relates a method for printing securitydocuments according to the preamble of the independent claim.

BACKGROUND ART

[0002] When printing security documents, in particular banknotes, caremust be taken to monitor the production carefully. An unaccounted lossof documents during the printing process has to be avoided.

[0003] It has been known to monitor the sheets that the securitydocuments are printed on. For this purpose, The sheets are provided withmachine readable identifiers, which are checked by the various printingstations of a security printing plant. This allows to detect a loss of asheet and to find the location where it was lost. This solutionrequires, however, a substantial amount of hardware, and in particular apowerful, dedicated network for exchanging the substantial amount datathat is generated in a large printing plant with high speed printers.

DISCLOSURE OF THE INVENTION

[0004] The problem to be solved by the present invention is to provide asystem of this type that allows to monitor printing in a large plantwhile keeping hardware, software and network requirements low.

[0005] This problem is solved by the method of claim 1 by attributing alocal computer to each printing station (or at least to each printingstation having a reader for the identifiers of the sheets). The localcomputer reads the identifiers of the sheets processed by the printingstation. The identifiers are collected and a plurality of them arecommonly transmitted at a time in a single data packet to a centraldatabase. This procedure reduces the amount of network trafficconsiderably.

[0006] Preferably, the local computer attributed to a given printingstation should check locally if all sheets of a batch have beenprocessed. This further reduces network traffic as compared to asolution where this type of monitoring is carried out by a centraldatabase. Furthermore, it allows an operator to check, without networkaccess, the status of a batch at the printing station. He can e.g. usethe local computer for printing a protocol that describes the result ofthe processing of a batch, e.g. by identifying the batch and listing anyfailures and inconsistencies during processing.

[0007] In order to allow a local computer to check processing of a givenbatch, it needs to know the identifiers of the sheets belonging to thebatch. For this purpose, the identifiers can be structured in such a waythat they reveal directly what batch a sheet belongs to. For improvedflexibility, though, a message listing the identifiers of the sheets ofa batch is transmitted from the central database to the local computerbefore the batch is processed.

[0008] The method according to the invention is especially suited forthe printing of banknotes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The invention will be better understood and objects other thanthose set forth above will become apparent when consideration is givento the following detailed description thereof. Such description makesreference to the annexed drawings, wherein:

[0010]FIG. 1 a banknote,

[0011]FIG. 2 a sheet with banknotes printed thereon,

[0012]FIG. 3 a printing plant for carrying out a preferred embodiment ofthe invention.

MODES FOR CARRYING OUT THE INVENTION

[0013] As mentioned above, the present invention is especially suitedfor printing banknotes and the following example will therefore discussa banknote printing process. It must be noted, though, that theinvention can be used for printing other type of security documentswhere a plurality of documents is printed onto sheets and the flow ofthe sheets is to be monitored.

[0014]FIG. 1 shows a simple banknote 1 with graphical illustrations 2,security features 3 and readable information 4 printed thereon.Printing, in this context, is to be understood in a broad sense andrefers to any procedures used for applying visible or invisible featuresto a support sheet, e.g. by applying an ink, by lamination or bymechanical treatment.

[0015] Banknote 1 further carries a serial number 5, which is anindividual number or string of characters unique to each banknote.

[0016] During manufacturing, a plurality of the banknotes 1 are printedon a single sheet 6, such as it is depicted in FIG. 2. Once printing issubstantially complete, the sheets 6 are cut for isolating theindividual banknotes 1.

[0017] Sheet 6 has a margin 7, which is generally not used for printingbanknotes thereon. In the present embodiment of the invention, thismargin carries a machine readable identifier 8, e.g. in the,form of abar code, as well as a human readable equivalent 9 thereof. The purposeof identifier 8 is described below.

[0018] During manufacturing, the sheets 6 are usually processed inbatches. A batch is a plurality of sheets 6, which are usually processedtogether, e.g. in a single shift. A batch may typically comprise betweenthousand and several ten thousand sheets.

[0019] A sophisticated security document, such as a banknote, carries aplurality of security features that make the document difficult to copyor falsify. The production of these security features generally requiresa plurality of steps to be carried out at different printing stations ina printing plant. The term printing station again is to be understood ina broad sense as any machine or location where a step required formanufacturing the document is carried out.

[0020]FIG. 3 shows a printing plant for printing security documents. Theplant comprises a plurality of printing stations 10, e.g. for applyingdifferent types of print. Usually, most of the printing stations carryout different types of printing steps, but some of them may be identicalfor processing batches in parallel manner, especially when a printingstep takes too much time to keep up with the desired rate of production.

[0021] Each, or at least most of, the printing stations 10 comprises oneor two readers 11 a, 11 b for reading the identifier 8 on the sheets ofthe processed documents. Preferably, two readers are provided, a firstreader 11 a being arranged at an input side of the printing station anda second reader 11 b being arranged at an output of thereof.

[0022] Furthermore, a writing device 12 is provided for writing themachine and human readable identifiers 8, 9 onto the sheets. Preferably,writing device 12 is arranged at the input side of one or more of theprinting stations that are used early in the manufacturing process.

[0023] A local computer 13 is attributed to each printing station.Preferably, there is one local computer for each printing station, eachequipped with a local printer 14 for printing manufacturing protocols.The local computers 13 are connected via a network 17 to a centraldatabase 16.

[0024] As described above, the sheets 6 are processed in batches. In theillustration of FIG. 3, each printing station 10 is shown whileprocessing a batch, e.g. topmost printing station processing havingprocessed a first part 15 a of a batch, while a second part 15 b of thebatch has not yet been processed. Once a batch 15 has been processedcompletely by a printing station, it is transferred to the next printingstation or to an intermediate storage location.

[0025] Database 16 contains “batch records” for all batches currentlybeing processed or waiting for further processing in the printing plant.Each batch record contains e.g. the following data

[0026] (a) a record number identifying the batch

[0027] (b) the sheets belonging to the batch, in particular theiridentifiers

[0028] (c) status of the batch (e.g. the processing steps that have beencarried out so far)

[0029] (d) total number of sheets

[0030] (e) number of successfully processed sheets

[0031] (f) type of document, order number

[0032] Entry (b) can either be explicit (e.g. a list of identifiers) orimplicit (e.g. by giving the lowest identifier and the number ofidentifiers, assuming the identifiers to be consecutive).

[0033] Furthermore, database 16 contains “sheet records” for all sheets,each sheet record e.g. containing

[0034] (a) the identifier of the sheet

[0035] (b) the batch the sheet belongs to

[0036] (c) reader data (an array identifying the readers the sheet haspassed and the times it passed them)

[0037] (d) status (processing so far successful, failure)

[0038] (e) serial numbers 5 of the documents on the sheet

[0039] Database 16 can comprise and maintain further data, such asinformation on the status of and the batches attributed to a givenorder.

[0040] Before a batch is being processed by a printing station 10,database 16 transfers a message listing the identifiers of the sheets ofthe batch to the local computer 13 of the printing station. The messagecan e.g. comprise the sheet records for each sheet in the batch or asubset of the sheet records, e.g. comprising entries (a) and (d)thereof.

[0041] While the batch is being processed by a printing station, thelocal computer 13 attributed to the printing station monitors the sheetspassing the readers 11 a, 11 b. For each sheet, local computer 13records the time it has passed each reader. If a sheet is damaged orprocessed in unsatisfactory manner, it is marked as failure. A dedicatedreader 11 c, which may e.g. be a portable reader operated by an operatorof the printing station, can be provided for reading the identifiers offailed sheets. When a sheet is marked as failure, the reason of failureis recorded for later storage in the status entry of the sheet record.The operation of readers 11 a and 11 b and the transfer of their data tocomputer 13 occurs real-time, i.e. the readers and the computer must beable to process each sheet as it passes. The data retrieved in this way,is stored in a local file on computer 13.

[0042] When a batch is complete, the operator of the printing stationalerts the corresponding local computer 13 manually. Now, local computer13 checks if all the sheets in the record have passed the input sidereader 11 a, thereby detecting any unprocessed sheets. It further checksif all the sheets have either passed the output reader 11 b or weremarked as failures, thereby detecting any sheets left within printingstation 10, e.g. as a consequence of a malfunction. Local computer 13then prints a status report on its local printer 14. This report can bechecked and signed by the operator of the printing station.

[0043] Local computer 13 can therefore monitor the processing of a batchand generate a status report without further help from database 16. Innormal operation, however, database 16 continuously updates theinformation stored in its records. For this purpose, it queries eachlocal computer 13 for recent readings at the corresponding printingstation, e.g. in time intervals of 10 minutes. Upon receipt of such aquery, the local computer 13 returns a data packet with a list of thereadings by at least one of the readers 11 a, 11 b or 11 c. This listcontains, for each reading

[0044] (a) the sheet identifier

[0045] (b) a reader identifier

[0046] (c) a time stamp of the reading in hours, minutes, seconds andfractions of seconds

[0047] (d) an error code (indicating if the reading indicates afailure).

[0048] In general, each data packet contains several readings fordifferent sheets. The data packet can further comprise the status of thecurrent batch, i.e. it specifies how much of the batch has beenprocessed and, after completion of the batch, a summary of theprocessing step.

[0049] The information in the data packet is then used by database 16 toupdate the data in the sheet and batch records.

[0050] As mentioned above, at least one of the printing stations 10 isprovided with a writing device 12 for generating the machine and humanreadable identifiers 8, 9. This is preferably a printing stationstanding at the very beginning of the processing of the sheets 6 so thatthe identifiers can be applied to the empty sheets, allowing to trackthe sheets over the whole production process. Before the sheets of abatch 6 are passed through the writing device 12, database 16 generatesthe identifiers for the sheets of this batch and passes them to thelocal computer 13 attached to the writing device. Hence, the identifiers8, 9 are generated under control of database 16. This allows database 16to automatically control batch size and numbering according to therequirements of a given order.

[0051] Usually, the serial numbers 5 of the banknotes will be printed byone of the printing stations, which, for this purpose, is equipped witha serial number printer 18. The serial number printer 18 is connected tothe corresponding local computer 13, which allows to generate a list ofthe serial numbers of all banknotes on a given sheet. For this purpose,database 16 can either send local computer 13 the serial numbersattributed to a batch before the batch is being processed at printingstation 10. Alternatively, if the serial numbers are generatedelsewhere, computer 13 can read the printed serial numbers from serialnumber printer 18 and store them, for each sheet, in its local file forlater transmission to database 16 during transmission of the datapacket. By maintaining a list of the serial numbers on each sheet indatabase 16, security can be increased further and tracking thebanknotes of a given sheet or batch becomes easier.

[0052] While there are shown and described presently preferredembodiments of the invention, it is to be distinctly understood that theinvention is not limited thereto but may be otherwise variously embodiedand practiced within the scope of the following claims.

1. A method for printing security documents (1), wherein the securitydocuments (1) are printed onto sheets (6), wherein each sheet (6) holdsa plurality of security documents (1) and a machine readable sheetidentifier (8), wherein the sheets (6) are fed through a plurality ofprinting stations (10) and wherein the identifiers (8) of the sheets (6)are electronically read in at least some of the printing stations (10),characterized in that a plurality of local computers (13) are providedand one local computer (13) is attributed to each printing station (10),and that the local computers (13) are connected to a central database(16), wherein the identifiers (8) of the sheets (6) processed at a eachprinting station (10) are read by the computer (13) attributed to theprinting station (10) and wherein the identifiers (8) of a plurality ofsheets (6) processed by the printing station (10) are transferred as apacket to the central database (16).
 2. The method of claim 1 whereinthe sheets (6) are processed in batches (15 a, 15 b), each batch holdinga plurality of sheets (6).
 3. The method of claim 2 wherein the localcomputer (13) attributed to a given printing station (10) checks if allsheets (6) of a given batch have been processed.
 4. The method of claim3 wherein at the end of the given batch the local computer (13) prints aprotocol describing a result of the processing of the batch by the givenprinting station (10).
 5. The method of one of the claims 2 to 4wherein, before a batch is processed by a given printing station (10), amessage listing the identifiers (8) of the sheets (6) of the batch istransmitted from the central database (16) to the local computer (13)attributed to the printing station (10).
 6. The method of one of thepreceding claims wherein the identifiers (8) are printed onto the sheets(6) in at least one printing station (10), wherein, for each batch, thecentral database (16) generates the identifiers (8) of the sheets (6) insaid batch, and transfers them to the local computer (13) attributed tothe printing station (10) printing the identifiers (8), and wherein thelocal computer (13) controls the printing of the generated identifiers(8) onto the sheets (6) of the batch.
 7. The method of one of thepreceding claims wherein the central database queries the localcomputers (13) for receiving the packets with the identifiers (8) of theprocessed sheets (6).
 8. The method of one of the preceding claimswherein, for each sheet (6), the time its identifier has been read at agiven printing station (10) is recorded and stored by the local computer(13) attributed to the given printing station (10).
 9. The method of oneof the preceding claims wherein the documents (1) are provided withindividual numbers and wherein, for each sheet (6), the numbers of thedocuments on said sheet (6) are stored in the database.
 10. The methodof one of the preceding claims wherein the documents (1) are banknotes.